I've noticed an extremely bad wobble from my C5 as of yesterday @70 MPH . (its a C5 2011 ) -Tire Pressure is 18# Front and 28# back and I weigh approx 170 Lbs.I have 3200 Miles on the bike and have on many occasions noticed the wobble but it was not bad....Sometimes the wobble would show up at speeds of 75 and above, and sometimes at around 78 MPH..I figured that was dependent on the type of road i was riding on... but now its consistent at 70, its bugging me because on our California Roads everyone is going at 80+ MPH... If I can't even ride safely at 70 MPH, then I'm screwed.....( I do have to occasionally take the freeways to get to the back roads I like & this bike should let me do that).WORK DONE: I took the swing arm off cause I broke the Stud that Holds the Shock and welded a new stud in its place..The "new" Stud is welded in the exact same spot as the OEM stud. The OEM was a Thru bolt/stud, and when we heated the stud up it came right off, leaving a clean Hole in its place... SO the new grade 8 Metric bolt went right through the original opening and was welded in place, likewise also making sure the chain Snails were put back in the correct place as before ( I had them marked with a Sharpie, the alignment looks good), The drum brake works fine and the bike rides well(below 70MPH). I don't think my working on the swingarm caused this issue.My concern is I may now have a C5 that I cannot ride over 70MPH with.... I am hoping there is a solution to this issue..WITHOUT having to spend a fortune...

Had it in e-mail May need some corrections and polish, may need some more things added but here it is for what it's worth...

The Royal Enfield UCE C5 (also known as the Classic 500 outside North America) was an all new model with an all new frame. It had less trail than previous models. This makes it a sharp handling bike but can lead to instability at higher speeds.

There have been numerous documented cases here on the forum of bikes that would weave and wobble uncontrollably at speeds of 50mph or higher. While I believe that all of these reports are true I also believe that the base design of the C5 is sound up the the intended top speeds of a stock bike. There are plenty of us who have taken our C5s to 80-85mph indicated on the speedometer with no instability whatsoever. This writing is concerned with only the C5, not G5, B5, or any of the older models.

To be clear here I am speaking of what I would call the "first generation C5" design: 18" wheels front and rear, Avon AM26 Roadrider tires in 110x80 18" and 90x90 18" sizes, fork with ends that hold the axle and project forward a bit. In 2012 some of the C5s started coming with 19" front wheels, wider tires, straight forks with no projecting ends, or any combination of the above. All of these changes would make the bike more stable. They were introduced as a "special" model but it seems this is now the standard. I would call bikes with any or all of these features "second generation C5s".

I'll say again, I believe that the base design of the C5 is sound up the the intended top speeds of a stock bike, 80-85mph. I further believe that most bikes exhibiting instability can be tamed and made stable with proper setup and assembly and WITHOUT steering stabilizers, 19" front wheels, or any other changed or added hardware. My bike will go to 80mph indicated with no wobble, I can take my hands off the bars. Others have reported the same. I truly believe the C5 basic design is sound and stable up to the top speed of the stock UCE engine.

For bikes that are exhibiting instability I would attribute it to one of three causes: 1) Improper dealer prep. (correctable) 2) Improper factory assemly. (correctable) 3) Improper manufacturing resulting in a misaligned frame or some other gross alignment anomaly. (difficult or impossible to correct)

Over many posts we have determined several common causes for instability problems and gotten many riders' bikes into top condition with no more instability. I wish to detail them here for all to read. I'll try to make them very detailed and basic so that even a new rider/mechanic should be able to check them even if they can't necessarily correct them. Further, I will try to order them with the most common and most easily correctable first. Check all of these items in the order in which they are listed. DO NOT proceed to later steps without ensuring the previous items are correct.

--Issue: Improper tire inflation.The solution: Set the front tire to 18psi and the rear tire to 24psi.

Yeah, that sounds too low. Do it anyway. The AM26 tires are very stiff bias ply tires. They will not overheat or wear prematurely at these pressures. I've got over 11,000 miles on my original tires and there's plenty of tread left.

This would fall under dealer prep. While the dealer should get this right it's an easy mistake to make. The owner's manual has one spec for solo riding and one for passenger, the frame is stamped with another which is probably more suited to riding with a passenger, the shop manual has another, and then of course the tires have a maximum pressure on them which has nothing to do with what they should be inflated to for any bike they're mounted on but many people use anyway.

The C5 is VERY sensitive to tire pressure. Simply running them too high can cause a wobble. In defense of dealers most of them are new to RE when the UCE bikes came out. They were all new to the C5 when it came out, even existing dealers. They may have been unaware how important this little detail is for this particular bike. I've never known any other bike that was this sensitive to tire pressure.

--Issue: Loose bolts.The solution: Tighten them.

This could fall under dealer prep, factory assembly, or neither. These bikes vibrate a lot and things that were tight can become loose, especially when they're new and tend to vibrate more. Go over the whole bike and check everything. Just put a wrench on any bolt you see and try to tighten it. You don't need a lot of force, if you put moderate force on and it doesn't move it's tight. If it moves easily it has come loose and should be tightened. You should be doing this regularly for the whole bike for the first few thousand miles. Things tend to rattle loose more while the bike is breaking in. Pay particular attention to the wheels, axles, and any bolts that hold different parts of the frame together or that hold the engine to the frame.

--Issue: Improper wheel alignment.The solution: Make sure the rear wheel is properly in line with the front wheel.The solution: Align the rear wheel to the front.

This would fall under dealer prep. Motorcycles need to have the rear wheel pointed directly at the front wheel to handle properly. The C5 has the same notched "snails" as other REs to adjust the chain tension and wheel alignment. REs are hand made and the frames are not always 100% straight and true. Don't trust the snails. Having it indexed to the same notch on both sides will make the wheel straight on some bikes but not others. I recommend using the string method to check your alignment. It's simple and doesn't require anything more than some string and a partner to hold the bike upright. A partner is needed since the center stand tends to interfere with the string if it's down.

The steering bearings are the bearing that connect the fork to the frame of the motorcycle. They may be called headset bearings, headstock bearings, or any number of other things. Basically, the fork tubes are general held by two clamps, an upper and a lower one usually called triple trees. On our bikes the lower clamp is a standard triple tree and the upper clamp is that beautifully sculpted nacelle that also holds the headlight. Anyway, they hold the fork legs at their ends and in the middle they are sandwiched over the head tube or steering tube. There is a bearing at the top and one at the bottom and the two clamps ride on these bearings to allow you to move the handlebars smoothly and effortlessly from side to side.

Now the two clamps need to be held together with just the right amount of force. Just right, the bars move smoothly. Too tight, the bars are hard to move. Too loose, the front end can clunk around because there's too much space around the bearings. Even worse, the more you ride like this the more it beats the hell out of the bearings and makes the situation worse, you may even need to replace the bearings if they get damaged.

You can do a few things to check the bearings. First, put the bike on the center stand and sit on it to get the front wheel off the ground. Move the bars back and forth. If they are hard to move the bearings are too tight. That probably won't be an issue.

Next sit on the bike with it in neutral. Lock the front brake and push the bars back and forth pretty hard. The forks should flex a good bit and let the rear wheel move back and forth just a little. You should feel the bike moving. If you feel a clicking or clunking coming from the area of the bearings it's a good bet the bearings are too loose and need to be tightened. It could also mean there is a problem with one or both fork legs but that's much less likely.

Another way to check is to put the bike on the center stand and have someone sit on it to get the front wheel off the ground. Grab the fork legs low down (on the aluminum) and push/pull back and forth. Use common sense, don't do it so hard that you pull the bike off the center stand. Again, if you feel a clicking or clunking then the bearings may be loose.

The cups that the bearings ride in tend to seat during the first 500-1000 miles. While they may have been fine when the bike was brand new they can loosen up as they seat. This goes doubly so for old bearings that get replaced. Make sure to check them several times over the first few hundred miles.

--Issue: Loose or wiggly swingarm.The solution: Check the torque on the swingarm bolt, check the condition of the swingarm bushings.

The swingarm is the horizontal piece of frame that holds the rear wheel. It's connected to the shocks/springs at the back to let the wheel go up and down, it pivots on a large bolt at the front, down below the rider's seat.

To check it put the bike on the center stand with the rear wheel in the air. Stand on the left side of the bike. Grab the swingarm on the left side of the bike near the rear wheel and alternate pulling it out to the left and pushing it in to the right of the bike. It may flex a little but you should not feel either excessive play or any clunking, it should not feel "loose". If it does the pivot bolt may be loose or the bushings may be damaged.

A little behind and above the footpegs are two large, chromed, plastic covers on the frame. Remove them from both sides of the bike and you'll see the swingarm pivot bolt and the nut that holds it. The torque spec on this bolt is 54ft.lbs. Tighten it and see if it was loose.

If the bolt is tight but there is still excessive play or clunking you may want to check the bushings. Inside the swingarm there are two bushings made of plastic with a brass or bronze liner. These are waht pivot on the pivot bolt. The pre-UCE bikes had these made of metal, not plastic. The plastic is certainly less strong but I've only seen one or two documented failures. With the bike on the center stand you can remove the pivot bolt and move the front of the swingarm down to inspect them. This is not for beginners. Take it to the shop if you're unsure of your abilities. It also can be a pain to get the bolt back in once you've removed it.

--Issue: Worn wheel bearings.The solution: Replace them.

I've seen a few bearing go bad on these bikes with very low mileage. It's rare but not unheard of. To check them put the bike on the center stand with the wheel in question off the ground. For the front wheel have someone hold the handlebars in place. Grab the wheel at the front or rear and push/pull it back and forth. If you fell clunking the bearing is probably bad. Spin the wheel, it should rotate smoothly. If it grinds, shudders, or doesn't feel smooth the bearings may be bad. With the rear wheel you will have the noise of the chain as the wheel rotates but it should still be failry easy to check the bearings.

This was the most diabolical gremlin for one of our members, and one that used to be common but rarely affects modern bikes. As I said before, the REs are hand made and may not be 100% straight and true. If pieces of the frame are assembled out of alignment or are manufactured out of alignment and then forced together it can create an internal stress within the frame. The really nasty bit here is that you may not notice it except when the bike gets to a particular speed and vibrates just right. At that point it can create a harmonic in the frame, causing it to wiggle and become unstable.

Our poor fellow board member had this with his rear fender. The factory had force the fender struts about 1 1/2" into the mount and then bolted it there. While investigating the problem he unbolted the fender and noticed it sprung out as soon as the bolt came loose. He removed the fender, rigged up a plate and tail light holder, and went for a ride: no more wobble. He drilled new mounting holes in the fender so he could mount it with no stress and the bike was then stable and trouble free.

The easiest way to check this is to remove the two bolts that hold the fender stut to the frame on one side. If it springs out of place the fender may be inducing undue stress on the frame and setting up a harmonic vibration at speed.

LOL !! That was an EXCELLENT way to put it Scott. And an Excellent write up ! Boy, just thinking back, my bike has come a long way. We all put a huge amount of effort into that issue. You should just post that up , whenever someone mentions the shakes.

If I could add:

Ensure that the notch or half moon shaped cut out, on the front of the rear fender, is fully seated up against the rubber bushing mounted to the frame . That soft bushing places the fender in the correct position and also deadens the oscillation in the whole tail section, caused by A LOT of airflow under that high set rear fender at high speed. That is a large heavy mass back there ,and you don't want it shaking around.

Also, adding some washers to take up the side to side play on the rear shock bushings, where they mount on the studs. There is a bit of play on those rubber bushes.

Another frame stress point..... The bottom rear motor mount. The long bolt that runs across the bottom rear of the engine. It should run strait across to where it threads into the side stand/motor mounting plate. And that plate should be strait and level. If not.... the holes in the plate may need to be enlarged, so they will line up properly with the corresponding mounting locations on the frame.

Always start with the last thing you worked on, in this case the swing arm. since you had the wheel off, check very carefully that you got it back on aligned properly. If you have a long straight edge, I use an old venetian blind hanger, and butt it against the rear tire as high as I can to get a true straight line reading then see how much it stands off the front tire, about a 1/8". Then do the other side. It should be the same distance. Don't trust the snails to be right. they are most often off between the two sides.Bare

Always start with the last thing you worked on, in this case the swing arm. since you had the wheel off, check very carefully that you got it back on aligned properly. If you have a long straight edge, I use an old venetian blind hanger, and butt it against the rear tire as high as I can to get a true straight line reading then see how much it stands off the front tire, about a 1/8". Then do the other side. It should be the same distance. Don't trust the snails to be right. they are most often off between the two sides.Bare

Thanks Bare, That what I am thinking too..I just rechecked the torque on the bolt and it was at 54 ft.lbs....took her for a quick ride and its still the same problem at 70 MPH, ..Now I'm going to do a thorough check for the Alignment..Cheers

Mine twiched too, which could lead to the dreaded oscillation.I discovered that my lower triple tree bolts were loose, whichwould initiate this wobble. Tightening them has given a new confidence to me. Not only has this reduced the wobble to very marginal, but it has improved the excessive front diveunder hard braking, that I was experiencing earlier. And I thoughtall along that there was bad/insufficient oil in my forks.

On a very recent high speed ride, the bike was very stable, exceptfor minor incidents of road cracks, making it wobble a bit, but the bikewould correct that all by itself. I think I can still improve this further, becausemy rear fender seems to be in tension (read misaligned). That should sought outthe issue very nicely. I have also observed that adding the bronze/brass shims overthe plastic bushing work very nicely like thrust washers and protect the bushes from abuse.

However, over the years, I have learned that there is a thing called "correct procedure" of doing things. So tightening the triple tree bolts may sound easy, but this has to be donein the correct steps, to make it work..........else it may make things worse. Therefore it is best left to people with sound knowledge (read your dealer) or by learning and researching things at your own end. Needless to say proper tools are absolute must. Not only do they make things easier but also do not destroy your hardware !!

Mine twiched too, which could lead to the dreaded oscillation.I discovered that my lower triple tree bolts were loose, whichwould initiate this wobble.

Bradey.. What Torque Specs did you use to tighten the Triple Tree Bolts?

I have also observed that adding the bronze/brass shims overthe plastic bushing work very nicely like thrust washers and protect the bushes from abuse.

What Plastic Bushings are you referring to? (is it the swingarm?)

However, over the years, I have learned that there is a thing called "correct procedure"

Bradey- I understand that correct procedure is extremely important to resolve & correct any issue. I'm meticulously following the steps and guidance offered by the forum members. I am attempting a step by step elimination process, and hoping I get closer to resolving this "WOBBLE ISSUE".Cheers

Just read through your post again, and trying to save you a whole lot of work and aggravation.... Your tire pressures are mis-matched. Too much air in the rear tire, shortening your rake angle even more. Try dropping that to 24 pSI. 18 front...24 back, or you could go 20 front ...26 back. Give those a try and see how it does.

Also.... Don't forget to check that front pinch bolt on the lower right fork leg. It's for the axle. That one likes to come loose.

I agree about that axle pinch bolt. I found that the stock bolt was not big enough. Handle enough torque to do the job it's supposed to do and I drilled the hole out and replaced it with the next size bigger bolt.

@Bradey..Will do, my next step is to check wheel alignment and I will do that by wednesday nite..Im basically following Scotties and the rest of the gangs advise and going through the steps..Im hoping to resolve this by this weekend.